Drawing Tablet Controls Laser In Real-Time

April 1, 2026 by 1 Comment

Some projects need no complicated use case to justify their development, and so it was with [Janne]’s BeamInk, which mashes a Wacom pen tablet with an xTool F1 laser engraver with the help of a little digital glue. For what purpose? So one can use a digital pen to draw with a laser in real time, of course!

Pen events from the drawing tablet get translated into a stream of G-code that controls laser state and power.

Here’s how it works: a Python script grabs events from a USB drawing tablet via evdev (the Linux kernel’s event device, which allows user programs to read raw device events), scales the tablet size to the laser’s working area, and turns pen events into a stream of laser power and movement G-code. The result? Draw on tablet, receive laser engraving.

It’s a playful project, but it also exists as a highly modular concept that can be adapted to different uses. If you’re looking at this and sensing a visit from the Good Ideas Fairy, check out the GitHub repository for more technical details plus tips for adapting it to other hardware.

We’re reminded of past projects like a laser cutter with Etch-a-Sketch controls as well as an attempt to turn pen marks into laser cuts, but something about using a drawing tablet for real-time laser control makes this stand on its own.

A Novel 555 Circuit In 2026

April 1, 2026 by 4 Comments

The humble NE555 has been around for over five decades now, and while during that time we’ve seen a succession of better and faster versions of the original, the circuits which surround it are pretty well known. There can’t be anything new in the world of 555s, can there? [Stephen Woodward] claims he’s made a novel 555 circuit, with his 1 MHz linear voltage to frequency converter. Since he’s been in love with the 555 since 1974, we’re inclined to trust him on this part.

It’s visibly the 555 astable oscillator we’re all familiar with, given the addition of a current source in place of the normal charging resistor. This makes for a much more linear sawtooth waveform, but it still doesn’t fix the linearity of the voltage to frequency curve. The novel bit comes in adding an extra resistor between the threshold and discharge pins, with a value calculated for a time constant with the capacitor to match the 555’s own switching delay. This provides the necessary compensation, and gives the circuit its linearity.

This is so brilliantly simple that it’s almost a shock that it’s new, but it’s also a great example of the old-school electronic engineer’s art. We can’t think of an immediate need for a 555 voltage to frequency converter on the Hackaday bench at the moment, but you can bet we’ll come back to this one if we do.

We had someone pushing a newer 555 variant to its limit, when we ran our component abuse challenge.

Running A Game On A PC With No System RAM

March 31, 2026 by 8 Comments

As a clear sign of how desperate these RAMpocalypse times are becoming, we have [PortalRunner] over on YouTube contemplating how to run modern-day software on a PC that has no sticks of that most precious PC-related commodity that is not printer ink. What fallbacks do we have when purchasing some sticks of DDR5 is inconceivable due to budgetary limitations or chronic sticker shock symptoms? As it turns out, quite a few.

Of course, it should be noted up front that none of these options are particularly good or desirable. The video starts with simply trying to push Linux to see how little RAM it really needs using boot arguments. This unfortunately soft-bricks the system if not enough RAM is allocated for boot. Next is the idea of leaning heavily into swap, as today’s SSDs ought to be a lot faster than memory page swapping from a HDD. Only this turns out to be also too slow to be usable due to the sheer overhead that this adds.

Even more desperate is to try and use the video RAM on GPUs as a kind of system RAM, which sort-off works, but also with enormous overhead and an if possible worse experience than running a system off basically a pure swap file. Ultimately the most viable method is to lean into the CPU’s many megabytes of cache and modify a CoreBoot BIOS image to simply not initialize system RAM.

As long as you can squeeze your software into the BIOS image and available CPU cache memory, you can run amazing software like the Snake clone in the video. Of course this concept could be expanded upon, and maybe even made to work with UEFI BIOSes, but there will probably not be anyone running Linux from a 32 MB L3 cache any time soon.

Continue reading “Running A Game On A PC With No System RAM” →

A Nebula Straight From The Stars To Your Table

March 31, 2026 by 1 Comment

Space may truly be the final frontier, but maybe that frontier can be closer than you thought. Pictures of nebulae and planets bring the colorful sights of deep space right to your screen. You may even have models of some of the rockets used for those missions on a shelf. However, did you know that you could even have a model of those nebulae or planetary surfaces from [NASA]?

While we have covered some distributed models from [NASA] here before, the catalog has expanded far past what 2016 had in store. Additionally, the catalog has been sorted into a more user-friendly, filterable interface than a simple GitHub repository. Most models even have a description attached, giving some basic background information on what the Crab Nebula is, for example.

There could always be more; there don’t appear to be many models of the space shuttle or some other expected files, but what is there is incredible. Some non-3D model files can also be found from star maps to full planetary maps.

While this file repository is cool and all, it’s not all [NASA] does. When not sending rockets deep into space for cool pictures, [NASA] has to make sure the Moon doesn’t explode. Was that a possibility at some point? Of course it has been!

LED Matrix Clock Proudly Shows Its Inner Wiring

March 31, 2026 by 9 Comments

Some projects take great care to tuck away wire hookups, but not [Roberto Alsina]’s Reloj V2 clock. This desktop clock makes a point of exposing all components and wiring as part of its aesthetic. There are no hidden elements, everything that makes it work is open to view. Well, almost.

The exception is the four MAX7219 LED matrices whose faces are hidden behind a featureless red panel, and for good reason. As soon as the clock powers up, the LEDs shine through the thin red plastic in a clean glow that complements the rest of the clock nicely.

[Roberto]’s first version was a unit that worked similarly, but sealed everything away in a wedge-shaped enclosure that was just a little too sterile, featureless, and ugly for his liking. Hence this new version that takes the opposite approach. Clocks have long showcased their inner workings, and electronic clocks — like this circuit-sculpture design — are no exception.

The only components, besides the Raspberry Pi Zero W and the LED matrices, are the 3D-printed enclosure with a few hex screws and double-sided tape. Design files and code (including the FreeCAD project file) are available should you want to put your own spin on [Roberto]’s design.

A hex dump of the first iteration of the small ELF file

How Small Can A Linux Executable Be?

March 31, 2026 by 28 Comments

With ever increasing sizes of various programs (video games being notorious for this), the question of size optimization comes up more and more often. [Nathan Otterness] shows us how it’s done by minifying a Linux “Hello, World!” program to the extreme.

A naive attempt at a minimal hello world in C might land you somewhere about 12-15Kb, but [Nathan] can do much better. He starts by writing everything in assembly, using Linux system calls. This initial version without optimization is 383 bytes. The first major thing to go is the section headers; they are not needed to actually run the program. Now he’s down to 173 bytes. And this is without any shenanigans!

A hexdump of the final ELF file, significantly smaller than the original
The final tiny ELF file

The first shenanigans are extreme code size optimizations: by selecting instructions carefully (and in a way a C compiler never would), he shaves another 16 bytes off. But the real shenanigans begin when he starts looking for spaces in the ELF header that he can clobber while the program is still accepted by Linux: now he can move his already tiny x86_64 code into these “vacant” spaces in the ELF and program headers for a final tiny ELF file weighing in at just 120 bytes.

P.S.: We know it is possible to make this smaller, but leave this as an exercise to the viewer.

An Oscilloscope The Way They Used To Be

March 31, 2026 by 2 Comments

It’s likely that Hackaday has a readership with the highest percentage of oscilloscope ownership among any in the world, and we’re guessing that most of you who fit in that bracket have a modern digital instrument on your bench. It’s a computer with a very fancy analogue front end, and the traces are displayed in software. Before those were a thing though, a ‘scope was an all-analogue affair, with a vacuum-tube CRT showing the waveform in real time. [Joshua Coleman] has made one of these CRT ‘scopes from scratch, and we rather like it.

Using a vintage two inch round tube, it includes all the relevant power supplies and input amplifiers for the deflection plates. It doesn’t include the triggers and timebase circuitry you’d expect from a desktop instrument though, so unless you add a sawtooth on its X input it’s only good for some Lissajous figures. But that’s not the point of a project like this one, because it’s likely even the cheapest of modern ‘scopes way exceeds any capabilities it would have even if it were fully formed. It’s a talking point and an attractive demonstration of a bit of early-20th-century physics, which probably many of us would appreciate if it were ours.

A video of the device is below the break, meanwhile we’ve taken a look in the past at the prehistory of the oscilloscope.

Continue reading “An Oscilloscope The Way They Used To Be” →